直徑1800mm的甲苯篩板精餾塔設(shè)計(jì)(全套CAD圖+說(shuō)明書(shū)+開(kāi)題報(bào)告+翻譯)
直徑1800mm的甲苯篩板精餾塔設(shè)計(jì)(全套CAD圖+說(shuō)明書(shū)+開(kāi)題報(bào)告+翻譯),直徑,mm,妹妹,甲苯,篩板,精餾塔,設(shè)計(jì),全套,cad,說(shuō)明書(shū),仿單,開(kāi)題,報(bào)告,講演,呈文,翻譯
畢業(yè)設(shè)計(jì)(論文)任務(wù)書(shū)
學(xué) 院: 機(jī) 械 工 程 學(xué) 院
題 目: 直徑1800mm的甲苯篩板精餾塔設(shè)計(jì)
起止時(shí)間:
學(xué)生姓名:
專(zhuān)業(yè)班級(jí):
指導(dǎo)老師:
教研室主任
院 長(zhǎng):
設(shè)計(jì)(論文)內(nèi)容及要求:
一、 已知設(shè)計(jì)參數(shù):
生產(chǎn)能力8萬(wàn)噸/年(300天)
進(jìn)料組成50%(質(zhì)量) 塔頂產(chǎn)品組成 >99%
塔底產(chǎn)品組成 <2%
操作壓力:常壓
進(jìn)料熱狀態(tài): 泡點(diǎn)進(jìn)料 冷卻水:
加熱蒸汽: 塔類(lèi)型:板式塔
環(huán)境:衡陽(yáng)室外
二、 設(shè)計(jì)內(nèi)容及設(shè)計(jì)工作量要求:
(1)按所給設(shè)計(jì)參數(shù)完成分離塔的施工圖設(shè)計(jì);
(2)繪制設(shè)計(jì)圖紙總計(jì)3張零號(hào)以上,其中要求手工繪圖
1張壹號(hào)以上;
(3)設(shè)計(jì)說(shuō)明書(shū)字?jǐn)?shù)不少于1.5萬(wàn)字,并要求統(tǒng)一用A4紙
打?。?
(4)翻譯3千左右漢字量的與畢業(yè)設(shè)計(jì)有關(guān)的英文資料;
(5)撰寫(xiě)相當(dāng)于3百漢字的英文摘要。
三、 主要參考資料:
《化工設(shè)備設(shè)計(jì)全書(shū)(塔設(shè)備)》
《化工原理》
《化工工藝設(shè)計(jì)手冊(cè)》
GB150-1998《鋼制壓力容器》
指導(dǎo)老師:
指導(dǎo)教師: 年 月 日
畢業(yè)設(shè)計(jì)(論文)
題 目 直徑1800mm的甲苯篩板精餾塔設(shè)計(jì)
學(xué)院名稱(chēng) 機(jī)械工程學(xué)院
指導(dǎo)教師
職 稱(chēng)
班 級(jí)
學(xué) 號(hào)
學(xué)生姓名
畢業(yè)設(shè)計(jì)(論文)開(kāi)題報(bào)告
設(shè)計(jì)(論文)題目
直徑1800mm的甲苯篩板精餾塔設(shè)計(jì)
設(shè)計(jì)(論文)題目來(lái)源
自選
設(shè)計(jì)(論文)題目類(lèi)型
工程設(shè)計(jì)
起止時(shí)間
一、 設(shè)計(jì)(論文)依據(jù)及研究意義:
本設(shè)計(jì)依據(jù)《化工工藝設(shè)計(jì)手冊(cè)》、GB150-1998《鋼制壓力容器》、JB/T4710-2005《鋼制塔式容器》以及HG20562-1998《塔設(shè)計(jì)技術(shù)規(guī)定》進(jìn)行。本設(shè)計(jì)的作用在于分離化工生產(chǎn)中常用到的兩種重要化工原料—苯和甲苯,意義重大。綜合考慮分離效率、生產(chǎn)制造成本、安裝及維護(hù)等因素,本設(shè)計(jì)采用篩板式精餾塔。
二、 設(shè)計(jì)(論文)主要研究的內(nèi)容、預(yù)期目標(biāo)(技術(shù)方案、路線(xiàn)):
本設(shè)計(jì)主要從化工工藝、材料選型、結(jié)構(gòu)設(shè)計(jì)以及塔的機(jī)械設(shè)計(jì)進(jìn)行設(shè)計(jì)。本設(shè)計(jì)路線(xiàn):分離任務(wù)—工藝流程描繪—工藝計(jì)算—材料選型—結(jié)構(gòu)設(shè)計(jì)—塔的機(jī)械設(shè)計(jì)—附屬設(shè)備選型。預(yù)期目標(biāo):希望通過(guò)本次的畢業(yè)設(shè)計(jì)能培養(yǎng)出獨(dú)立設(shè)計(jì)的能力,為以后的工作
打下好的基礎(chǔ),更好的與社會(huì)接軌。
三、設(shè)計(jì)(論文)的研究重點(diǎn)及難點(diǎn):
重點(diǎn)是:依據(jù)分離任務(wù)進(jìn)行分離工藝的計(jì)算確定塔體和塔板的工藝尺寸,由塔的操作條件完成塔體和裙座的厚度計(jì)算,由塔的安裝環(huán)境對(duì)塔進(jìn)行機(jī)械校核。
難點(diǎn):一、由于資料可能不全,設(shè)計(jì)時(shí)沒(méi)有經(jīng)驗(yàn),造成各種誤差。
二、分離效率的保證
三、塔的結(jié)構(gòu)設(shè)計(jì)
四、設(shè)計(jì)(論文)研究方法及步驟(進(jìn)度安排):
1月6日至2月15日:了解我們所要設(shè)計(jì)的試驗(yàn)裝置,為進(jìn)行設(shè)計(jì)做準(zhǔn)備;
2月16日至2月28日:進(jìn)行參觀(guān)實(shí)習(xí);寫(xiě)開(kāi)題報(bào)告;
2月28日至3月18日:查閱資料,找設(shè)計(jì)依據(jù),理出設(shè)計(jì)思路;
3月18日至4月24日:具體的結(jié)構(gòu)和系統(tǒng)設(shè)計(jì),求得設(shè)計(jì)的各種依據(jù);
4月25日至5月25日:設(shè)計(jì),畫(huà)出設(shè)計(jì)圖紙;
5月26日至5月28日;整理圖紙,進(jìn)行打?。慌虐嬖O(shè)計(jì)說(shuō)明書(shū)。
5月29日至5月31日:準(zhǔn)備答辯。
五、進(jìn)行設(shè)計(jì)(論文)所需條件:
1、要有充分的資料(與塔設(shè)備有關(guān)、與分離工藝有關(guān))。
2、到相關(guān)單位進(jìn)行實(shí)習(xí),了解塔設(shè)備的結(jié)構(gòu)及生產(chǎn)過(guò)程中的
各種控制方案和原理。
3、設(shè)計(jì)所需設(shè)計(jì)方法、軟件、工具等。
六、指導(dǎo)教師意見(jiàn):
簽名: 年 月 日
摘要:在化工、煉油、醫(yī)藥、食品及環(huán)境保護(hù)等工業(yè)部門(mén),塔設(shè)備是一種重要的單元操作設(shè)備。塔器即是高徑比很大的設(shè)備。它可以實(shí)現(xiàn)氣(汽)-液相或液-液相之間的充分接觸,從而達(dá)到相際間進(jìn)行傳質(zhì)及傳熱的目的。常見(jiàn)的、可在塔設(shè)備中完成的單元操作有:精餾、吸收、解吸和萃取等。精餾是分離液體混合物最常用的一種單元操作,即利用液相混合物中各相分揮發(fā)度的不同,使易揮發(fā)組分由液相向氣相轉(zhuǎn)移,難揮發(fā)組分由氣相向液相轉(zhuǎn)移。苯和甲苯都是化工生產(chǎn)中的重要原料,屬于芳香族化合物。因此,將苯和甲苯從其混合物中分離出來(lái)加以提純,意義重大。塔設(shè)備按結(jié)構(gòu)形式可分為填料塔和板式塔。由于板式塔的分離效果比填料塔好,考慮到苯和甲苯的物性以及生產(chǎn)費(fèi)用問(wèn)題,本設(shè)計(jì)選用化工生產(chǎn)中被廣泛采用的篩板塔。因?yàn)楹Y板塔較其他類(lèi)型塔有如下優(yōu)點(diǎn):結(jié)構(gòu)簡(jiǎn)單,成本低,塔板效率高,安裝維修方便。本設(shè)計(jì)的主要內(nèi)容是:過(guò)程的物料衡算、熱量衡算,工藝計(jì)算,結(jié)構(gòu)設(shè)計(jì)和校核,機(jī)械強(qiáng)度設(shè)計(jì)(特別是要考慮風(fēng)載荷和地震載荷的影響),管路選擇,貯罐、換熱器的選型,繪制工藝流程圖,以及塔的施工圖設(shè)計(jì):包括總裝配圖和若干零件圖。
關(guān)鍵詞: 精餾 篩板塔 工藝計(jì)算 結(jié)構(gòu)設(shè)計(jì) 強(qiáng)度校核
Abstract: The tower equipment is an important unit operation equipment in industry sectors, for instance, chemical industry, refinery, medicine, food, environmental protection, and so on. It can realize the steam between the liquid phase or the fluid - liquid phase contact deeply, thus achieving the border carries on the mass transfer and the heat transfer goal. The distillation is the separation of liquid mixtures most commonly used as an unit operation in chemical industry, oil refining, petrochemical and other industries. The design mission is to produce an important chemical raw material from a mixture of benzene and toluene, it will be a great significance if the material can be separated from its mixture of benzene and toluene. Taking into account the structures of benzene and toluene, as well as the production costs, the designer selected the sieve plate distillation column which are widely used in chemical production.
As compared to other types of towers, the sieve-plate column tower has the following advantages: simple structure, low cost, high efficiency tray, tower installation and maintenance easy. The main elements of the design is: Process material balance, heat balance, process calculation, structural design and verification, mechanical strength of the design, pipe selection, storage tank, heat exchanger, drawing process maps, design of tower construction plans, including the total number of assembly drawings and parts diagram.
Key Words: Distillation Sieve-plate column Process calculation
Structural design Check of strength
目錄
第一章 概述…………………………………………………………1
第二章 流程的設(shè)計(jì)及說(shuō)明…………………………………………3
第三章 工藝設(shè)計(jì)計(jì)算………………………………………………4
3.1 物料衡算……………………………………………………4
3.2 確定塔內(nèi)操作溫度…………………………………………5
3.3 確定回流比及塔板數(shù)………………………………………6
3.4 塔設(shè)計(jì)計(jì)算…………………………………………………8
3.4.1 精餾段計(jì)算……………………………………………8
3.4.2 提餾段計(jì)算 …………………………………………20
3.5 精餾塔高度的計(jì)算………………………………………33
第四章 精餾塔的結(jié)構(gòu)設(shè)計(jì)…………………………………………34
4.1 塔盤(pán)………………………………………………………34
4.2 各接管及法蘭選擇………………………………………35
4.3 人孔………………………………………………………40
4.4 操作平臺(tái)和扶梯…………………………………………41
4.5 裙座………………………………………………………42
4.6 吊柱………………………………………………………43
第五章 塔體和裙座的機(jī)械設(shè)計(jì)……………………………………45
5.1 選擇材料和確定參數(shù)……………………………………45
5.2 計(jì)算筒體和封頭的厚度…………………………………46
5.3 塔的自振周期的計(jì)算……………………………………46
5.4 塔體的質(zhì)量載荷計(jì)算……………………………………47
5.5 風(fēng)載荷及風(fēng)彎矩計(jì)算……………………………………50
5.6 地震載荷及彎矩的計(jì)算…………………………………52
5.7 各載荷引起的軸向應(yīng)力…………………………………54
5.8 筒體和裙座危險(xiǎn)截面的強(qiáng)度與穩(wěn)定性校核……………56
5.9 筒體和裙座水壓試驗(yàn)應(yīng)力校核…………………………57
5.10 裙座和塔體的連接焊縫校核……………………………59
5.11 基礎(chǔ)環(huán)設(shè)計(jì)………………………………………………60
5.12 地腳螺栓計(jì)算……………………………………………61
第六章 附屬設(shè)備的計(jì)算及選型 …………………………………65
6.1 貯罐………………………………………………………65
6.2 換熱器……………………………………………………66
參考文獻(xiàn)……………………………………………………………69
英文翻譯……………………………………………………………70
謝辭…………………………………………………………………85
iv
英文翻譯
Chinese J.of Chem.Eng.,9(2)141—144(2001)
Operation of a Batch Stripping Distillation Column
xu Songlin(許松林) ,Jose Espinosab,Hector E.Salomoneb and Oscar A.Iribarrenb
a National Engineering Research Center for Distillation Technology,Tianjin University,
Tianjin 300072,China
b Institute for Development and Design INGAR ,
Conicet,Santa Fe,Argentina
Abstract A stripping batch distillation column is preferred when the amount of the light component in the feed is small and the products are to be recovered at high purity.The operation modes of a batch stripping are believed to be the same as those of a rectifier. However.the control system of a stripper is different. In this paper,we explore three different control methods with Hysys(Hyprotech Ltd.1997)for a batch stripper.The main difference is the control scheme for reboiler liquid level:(a)controlled by reflux flow;(b)controlled by reboiler heat duty;(c)controlled by bottom product flow. The main characteristics of operating a batch stripper with different control scheme are presented in this paper.Guidelines axe provided for the startup of a batch stripper,the effects of some control tuning parameters on the column performance are discussed.
Key words batch stripper.control.Operation
1 INTRODUCTON
Batch process is becoming more popular as chemical process industries move toward manufacturing fine and specialty chemicals,where flexibility is a key issue due to the frequent change of product demandBatch distillation columns are inherently flexible,as a single column call separate many different components from a multicomponent feed.Thus the use of batch distillation is becoming more important for the seperation and purification of high—value chemicalsin many chemical ,food,and pharmaceutical industries.Traditionally the most popular kind of batch distillation column is the so-caled rectilying column.which has a large reboiler,to which al the feed is charged.a(chǎn)n different products are removed from the top. There are three ways to operate a rectifying column[2].They are:(1)constant reflux and variable distillate composition,(2)variable reflux an d constant distillate composition of key component,(3)optimal reflux policy which trades of(1)and(2)and is based on the most profitable operation.
Batch stripping column is opposed to a batch rectifier. It has its storage vessel at the top and the products leave the column at the bottom . A stripping batch distilation column is preferred when the amount of the light component in the feed is small and the products are to be recovered at high purity[4,5].
The operation modes of a batch stripping are believed to be the same as those of a rectifier. However.the control system of a stripper is different.In this paper,we explore three different control methods with Hysys(Hyprotech Ltd.1997)for a batch stripper.The control schemes are shown in Fig.1. The main difference is the control scheme for reboiler liquid level:(a)controlled by reflux flow,(b)controlled by reboiler heat duty,(c)controled by bottom product flow .The main characterics of operating a batch stripper with different control scheme are presented in this paper.Guidlines are provided for the startup and the effect of so e control turning parameters on the column performance are discussed.
2 EXPERIMENTAL APPARTUS FOR THE SIMULATIONS
The experimental apparatus in the simulations is the same for the three control schemes.The stripping column has a reboiler,a condenser and 15 trays.The volumes of the reboiler and the condenser are 2m3 and 5m3,respectively.The diameter of the column is 0.5 m.The feed is the mixture of methanol(0.05)and ethanol (0.95)(mole fraction).The liquid percent level set point for the reboiler is 50% and the mixture takes 80% of the whole volume of the condenser.At the beginning,the trays are dry startup,but the reboiler is charged with the same mixture to the liquid level set point.The specification of bottom product ethanol is 0.999.All the simulated experimental procedures are that the stripper is started up till the specification of the heavy key composition is reached,then the bottom product valve is opened so that the product leavesthe column,the product valve is shut down when the product composition declines to the specification.
3 RESULTS AND DISCUSSION
3.1 Control reboiler Hquid level by reflux flow
In this control scheme【Fig.1(a)】,the reboiler liquid percent level is controlled autom atically by reflux flow,the reboiler heat input and bottom product flow are controled manualy. At the beginning,the reboiler heat in put is set fixed.The reboiler liquid level declines as the light com ponent is vaporized.Which will cause reflux flow down the reboiler automatically.The control of the reboiler liquid level is reversible.So when the reboiler liquid level is higher,there wil be less reflux flow an d vice versa. When the composition of heavy key component gets to its specification,the bottom product flow valve is opened;once it declines to the specification,the bottom product flow valve is shut down manualy.In this case,when ethan ol corn -position reaches 0.999,the bottom product flow valve is opened ,when ethan l is less than 0.999 the bottom product flow valve is shut down.
The dynamic process of this operation mode is shown in Fig.2.There is a time lag between the reboiler liquid level an d reflux flow ,especially when the number of stages is large.In order to get a stable reboiler liquid level control during the whole operation,two aspects should be considered carefully.0ne is to use an appropriate reflux valve. If the reflux valve is oversized,the reboiler liquid level controller wil get more reflux flow to the reboiler than the set point when the liquid level declines. Then the reflux flow valve will be closed. This makes the reboiler liquid level fluctuate frequently.One case is shown in Fig.3.In this situation the heavy key component composition in the bottom is unstable. The other aspect is that the tuning parameter of the reboiler liquid level should be chosen appropriately when a proportional only bottom level controler is employed.The proportional gain of the controler should be between 4.0and 8.0.If is too small,it is difficult to get a stable reboiler liquid level contro1.Fig.4 shows the relation between reboiler liquid percent level and for the same reboiler duty.From Fig.4.it is obvious that if is less than 4.0 the liqui d percent level in the reboiler is far away from the set point level 50%.If is between 4.0 and 8.0,the liquid level in the reboiler is near the set point.
3.2 Control reboiler liquid level by reboiler heat input
In this control scheme [Fig.1(b)】,the reboiler liquid level is controlled by reboiler duty automatically,reflux and bottom products flow are controlled manually.At the beginning,the reflux flow valve is opened to a fixed value.Reboiler liquid level increases,which will cause heat input to the reboiler.The action of the reboiler liquid level controler is direct,which means that the higher the reboiler liquid level,the more the heat input to the reboiler and vice versa.When the com position of the heavy key component in the reboiler gets to its specification.the bottom product flow valve is opened manuly. When the heavy key component com position decreases to 0.999,the valves for bottom product an d reflux flow are shut down manually.Fig.5 shows the dynamic process of this operation mode. It is obvious that the boil up mass flow and the liquid levels of condenser and reboiler are fluxed at the startup of the operation.This is due to the dynamic responsiveness of reboiler heat input to the liquid level controller.
3.3 Control reboiler Hquid level by bottom product flow
The reboiler liquid level is controled by bottom product flow in this control scheme[Fig.1(c)】.This scheme is similar to the third control mode for a rectifier.in which the reboil ratio is variable. In order to get the bottom product specification,a total reboil process should be established at the beginning of the operation.The action of the reboiler liquid level controller is direct,which means that the higher the liquid level,the more the bottom product flow and vice versa.
Figure 6(b)shows that at the startup of this operation,the liquid levels in both reboiler and condenser are oscillated,since it is difficult to meet the requirement for the total reboil at the beginning of the operation,for the reflux flow and reboiler heat input are operated manually.
4 CONCLUSION
The dynamic simulation with Hysys for the operation of a batch stripping distillation column indicates the main characterics of this kind of column,in which three different control schemes are employed.In the first scheme,reboil ratio is constant with variable bottom product com position;in the second scheme,reboil ratio is variable and the heavy key component composition in the bottom product is nearly constant,and the third is an optim al operation which could obtain more profit. Among these three control modes,the third is the most difficult to operate,since both controllers for reflux flow and reboiler heat input are operated manually.This work demonstrates the operation of a batch stripping column,provides some practical guidlines for the startup and operation of the column,shows how the column can be run under different operating modes,and clarifies the effect of some key control tuning on the column performance. However,this work is a dynamic simulation. The practical operation of a batch stripping distillation column still needs to be investigated in detail.
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3 Yang,zh.C.,Yu,G.C.(K.T. ),Mo,zh.M.,e£a/., t
“Study on optimal strategies and microcomputer control of
batch distillation(Ⅱ)Batch distillation column and its microcomputer
control”,J.(Chem.Ind.Eng.(China,40(3),
28 一286(1989).(in Chinese)
4 Lotter, S. P., Diwekar, U. M ., “Shortcut models and
feas ibility consideration for emerging batch distillation
columns”,Ind.Eng.Chem.Res.,36(4),760—767(1997).
5 Scrensen,E.,Skogestad,S.,“Comparison of regular and
inverted batch distillation”,Chem. Eng. Sci.,51 (22),
4949.一4962 of 1996).
分批沖孔模板精餾塔的操控
許松林,Jose Espinosab,Hector E.Salomoneb,Oscar A.Iribarrenb
a 中國(guó) ,天津,300072,天津大學(xué),國(guó)家精餾工程技術(shù)研究中心
b 阿根廷,桑塔費(fèi),康尼賽特,INGAR發(fā)展與設(shè)計(jì)學(xué)院
摘要 當(dāng)大量的輕的成分在流量中很少和高純度產(chǎn)品回收時(shí)分批沖孔模板精餾很重要,批量精餾塔的操控與鎮(zhèn)流器的作用是相同的。然而,沖孔模板的控制系統(tǒng)是不同的。在這篇論文里,我們探索沖孔模板三種不同的控制方法:Hysys(Hyprotech Ltd.1997),最主要的不同之處是重沸器液相控制圖;(a)以回流量控制;(b)以重沸器熱負(fù)載控制;(c)以底部產(chǎn)品流量控制。在此論文里闡述分批沖孔模板精餾塔的操控最主要的特征是不同的控制流程圖,分批沖孔模板控制開(kāi)始時(shí)提供了準(zhǔn)則,將要討論一些柱面上的控制調(diào)諧參數(shù)。
圖1分批沖孔模板的控制流程
1-塔體;2-重沸器;3-冷卻機(jī);4-整流器;LC-液面控制器;PC-壓力控制器
關(guān)鍵詞 分批沖孔模板 控制 操作
1 簡(jiǎn)介
隨著化工工廠(chǎng)向著大規(guī)模精細(xì)生產(chǎn)和專(zhuān)業(yè)化工產(chǎn)品方向發(fā)展,批量生產(chǎn)變得比較流行,這樣簡(jiǎn)易方法對(duì)于產(chǎn)品需求的頻繁變化起關(guān)鍵作用。批量精餾塔是固有簡(jiǎn)易特性的,正如一個(gè)柱可以由一個(gè)多組分供給分成許多不同的組份,這樣批量精餾的用途對(duì)于一些化學(xué),食品和藥物公司的高價(jià)值的化工產(chǎn)品的分離和提純變得越來(lái)越重要。
傳統(tǒng)的,最流行的批量精餾方法被稱(chēng)為整流柱,它有一個(gè)大的重沸器,對(duì)它所有的供給都是變化的,并且不同產(chǎn)品從頂部分離開(kāi)。操作整流塔有三種方法:(1)回流量為恒量并且精餾組份為變量,(2)回流量為變量并且精餾的主要組份為恒量,(3)最佳回流量協(xié)調(diào)了(1)和(2)并且建立在最經(jīng)濟(jì)的試驗(yàn)。
批量沖孔模板與批量整流是相反的。在它的頂端有它的儲(chǔ)存容器并且產(chǎn)品從塔的底部分離出。當(dāng)大量的輕的成分在流量中很少和高純度產(chǎn)品回收時(shí)分批沖孔模板精餾很重要。
批量精餾塔的操控與鎮(zhèn)流器的作用是相同的。然而,沖孔模板的控制系統(tǒng)是不同的。在論文中,我們探索Hysys(Hyprotech Ltd.1997)的批量沖孔模板三種不同的控制方法,圖表1給出了控制圖。最主要的不同之處是重沸器液相控制圖;(a)以回流量控制;(b)以重沸器熱負(fù)載控制;(c)以底部產(chǎn)品流量控制。
(a)底部產(chǎn)品的組分
(b)塔體中的溫度
(c)質(zhì)量流量
(d)頂部和底部的流量
在此論文里闡述分批沖孔模板精餾塔的操控最主要的特征是不同的控制流程圖,分批沖孔模板控制開(kāi)始時(shí)提供了準(zhǔn)則,將要討論一些柱面上的控制調(diào)諧參數(shù)。
2 模擬實(shí)驗(yàn)儀器
模擬實(shí)驗(yàn)儀器和三種控制圖是相同的,脫模塔有個(gè)重沸器和2 m 3和5 m 3的冷凝器,他的直徑是0.5m.供給成分是甲醇(0.05)和乙醇(0.95)(餾分)的混合物。占冷凝器容量的80%,開(kāi)始時(shí),板是干啟動(dòng)的,但是重沸器是由相同的混合液的液相點(diǎn)控制的。底部產(chǎn)品乙醇的規(guī)范是0.999.所有的仿真實(shí)驗(yàn)程序是從沖模開(kāi)始直到關(guān)鍵的組份達(dá)到規(guī)范,然后底部產(chǎn)品閥開(kāi)啟使產(chǎn)品分離,當(dāng)產(chǎn)品組份低于規(guī)范時(shí)產(chǎn)品閥關(guān)閉。
3 結(jié)果和討論
3.1 通過(guò)回流量控制重沸器液面
在控制圖中【圖表1(a)】,重沸器液相百分比是由回流量自動(dòng)控制的,重沸器的熱輸出和底部產(chǎn)品的流量是手動(dòng)控制的。開(kāi)始時(shí),重沸器的熱輸出是設(shè)定的,重沸器的液面隨著輕成分的蒸發(fā)而降低,這將導(dǎo)致回流自動(dòng)地流向重沸器。重沸器的液面控制是可逆的,所以當(dāng)重沸器的液面較高時(shí),回流量將較少。當(dāng)關(guān)鍵組份是成分達(dá)到其規(guī)范時(shí),底部的閥開(kāi)啟,一旦它低于規(guī)范,底部產(chǎn)品流出閥就手動(dòng)關(guān)閉,這樣的話(huà),當(dāng)乙醇成分達(dá)到0.999,底部產(chǎn)品流出閥開(kāi)啟,當(dāng)乙醇成分低于0.999,底部產(chǎn)品流出閥關(guān)閉。
圖表3重沸器液面的波動(dòng)
圖表2表示了此操作模式的動(dòng)態(tài)過(guò)程。在重沸器液面和回流之間存在時(shí)間滯后,尤其是當(dāng)階段數(shù)目很大時(shí)。為了在整個(gè)控制中達(dá)到一個(gè)穩(wěn)定的重沸器的液面。必須仔細(xì)考慮兩個(gè)方面。如果回流閥過(guò)大,當(dāng)液面降低時(shí),重沸器的液面控制器將從重沸器得到比預(yù)設(shè)多的回流量。然后回流閥將會(huì)關(guān)閉。這使重沸器液面頻繁波動(dòng)。圖表3展現(xiàn)出了一種情況,在這種情況底部關(guān)鍵成分的組成是不穩(wěn)定的,另一方面是重沸器的液相參數(shù)應(yīng)該合理選擇盡當(dāng)?shù)撞靠刂破鞯谋壤囉脮r(shí)。控制器的比例增益Kp應(yīng)該在4.0和8.0之間。如果Kp值太小,就很難使重沸器液面控制達(dá)到穩(wěn)定。圖表4展示了重沸器液相百分比與相同的重沸器的Kp值之間的關(guān)系。從圖表4中,很明顯的看出如果Kp值低于4.0時(shí)重沸器的液相百分比將低于預(yù)設(shè)值的50%。如果Kp值在4.0和8.0之間,重沸器的液面會(huì)處在預(yù)設(shè)值的附近。
圖表4 Kp值對(duì)重沸器液面的影響
3.2 通過(guò)重沸器的熱輸出控制重沸器的液面
在控制圖中【圖表1(b)】中,重沸器的液面是由重沸器的負(fù)載自動(dòng)控制的,回流和底部產(chǎn)品的流出是手動(dòng)控制的。開(kāi)始時(shí),回流閥須有一個(gè)特定值。重沸器的液面增加將導(dǎo)致對(duì)重沸器的熱輸入。重沸器的液面控制器的功能是直接的,這意味著重沸器液面越高,重沸器的熱輸入越多。當(dāng)關(guān)鍵組份是成分達(dá)到其規(guī)范時(shí),底部的產(chǎn)品流出閥手動(dòng)關(guān)閉。當(dāng)關(guān)鍵組份是成分降至0.999時(shí),底部產(chǎn)品流出閥和回流閥也手動(dòng)關(guān)閉。圖表5表示了此操作模式的動(dòng)態(tài)過(guò)程。很明顯的看出煮沸的大量流量和冷凝器的液面以及重沸器都回流至控制初期。這是由于重沸器的動(dòng)態(tài)響應(yīng)度的熱輸入對(duì)控制器的液面的影響。
(b)溫度
(c)質(zhì)量流量
(d)流量
(e)重沸器熱負(fù)載
3.3通過(guò)底部產(chǎn)品流量控制重沸器液面
通過(guò)底部產(chǎn)品流量控制重沸器液面的控制圖表示在[圖表1(c)]中。這個(gè)圖與整流器的第三種控制模式,其中重沸比例是可變的。為了使底部產(chǎn)品規(guī)范,全部的重沸過(guò)程應(yīng)建立在控制的初始值。重沸器的液面控制器的功能是直接的,這意味著重沸器液面越高,重沸器的熱輸入越多。
(a)產(chǎn)品組成
(b)流量
(c)質(zhì)量流量
(d)溫度
圖表6(b)表示了控制過(guò)程的初始階段,在重沸器和冷凝器中的液面振動(dòng),因?yàn)楹茈y達(dá)到整個(gè)重沸開(kāi)始時(shí)的需求,回流量和重沸器的熱輸入都是手動(dòng)控制的。
4 結(jié)論
Hysys的動(dòng)態(tài)模擬分批沖孔模板精餾塔的操控實(shí)驗(yàn)表明這種塔的主要特性,其中是實(shí)施了三種不同的控制流程。在第一種流程中,回流率是隨底部產(chǎn)品的成分對(duì)應(yīng)變化的;在第二種流程中回流率是變化的,底部產(chǎn)品的成分是接近不變的,而第三種流程會(huì)更經(jīng)濟(jì)一些的。在這三種控制模式中,第三種最難控制,因?yàn)榛亓髁亢椭胤衅鞯臒彷斎攵际鞘謩?dòng)控制的。
這項(xiàng)工作證明了分批沖孔模板的實(shí)驗(yàn),為塔體的控制和開(kāi)始提供了一些實(shí)際的流程表明了塔體能夠在不同的操作模式下運(yùn)作,并且闡述了一些關(guān)鍵的控制參數(shù)。然而,這項(xiàng)工作只是一個(gè)動(dòng)態(tài)模擬。分批沖孔模板精餾塔的操控仍然需要詳細(xì)的調(diào)查。
參考文獻(xiàn)
1 Salomone,H.E.,Chiotti,O.J.,Iribarren,O.A.,“Short.cut
design procedure for batch distillation”,Ind.Eng. Chen].
Res.,36 (1),13 一136(1997).
2 Sundaram,S.,Evans,L.B.,“Shortcut procedure for simulating
batch distillation operations”,Ind. EI . en].
Res.,32(3),511— 518(1993).
3 Yang,zh.C.,Yu,G.C.(K.T. ),Mo,zh.M.,e£a/., t
“Study on optimal strategies and microcomputer control of
batch distillation(Ⅱ)Batch distillation column and its microcomputer
control”,J.(Chem.Ind.Eng.(China,40(3),
28 一286(1989).(in Chinese) ’
4 Lotter, S. P., Diwekar, U. M ., “Shortcut models and
feas ibility consideration for emerging batch distillation
columns”,Ind.Eng.Chem.Res.,36(4),760—767(1997).
5 Scrensen,E.,Skogestad,S.,“Comparison of regular and
inverted batch distillation”,Chem. Eng. Sci.,51 (22),
4949.一4962 of 1996).
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